(Anglais) The authors have studied the elastic properties of radio frequency sputtered phase pure, stoichiometric, and dense hydroxyapatite films by nanoindentation. The measured elastic modulus values have been compared to ab initio calculated data. The calculation technique was based on the determination of all elastic constants. The calculated and measured elastic modulus values differ by ~ 10%. The good agreement indicates that the elasticity of hydroxyapatite can be described using ab initio calculations, establishing the elastic modulus thereof.